Method and apparatus for processing data in wireless communication system

ABSTRACT

The present disclosure relates to a communication method and system for converging a 5 th -Generation (5G) communication system for supporting higher data rates beyond a 4 th -Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. 
     A method for processing data by a reception device and the reception device are provided. The method includes receiving a radio link control (RLC) packet data unit (PDU), transferring an RLC service data unit (SDU) acquired from the RLC PDU from an RLC layer to a packet data convergence protocol (PDCP) layer regardless of a number of the RLC PDU, and deciphering the RLC SDU. The reception device includes a transceiver configured to transmit and receive signals; and a controller configured to receive an RLC PDU, transfer an RLC SDU acquired from the RLC PDU from an RLC layer to a PDCP layer regardless of a number of the RLC PDU, and decipher the RLC SDU.

PRIORITY

This application claims priority under 35 U.S.C. § 119(a) to a KoreanPatent Application filed on Jan. 16, 2017 in the Korean IntellectualProperty Office and assigned Serial No. 10-2017-0007159, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND 1. Field of the Disclosure

The present disclosure relates to a method and an apparatus forprocessing data in a wireless communication system, and moreparticularly, to an out-of-sequence deciphering method that acceleratesdata processing of a terminal and an apparatus for performing the methodin a mobile communication system.

2. Description of the Related Art

To meet the demand for wireless data traffic which has increased sincethe deployment of fourth generation (4G) communication systems, effortshave been made to develop an improved fifth generation (5G) or pre-5Gcommunication system. Therefore, a 5G or pre-5G communication system isalso referred to as a “beyond 4G network” or a “post long term evolution(LTE) system.” A 5G communication system is considered to be implementedin higher frequency (mmWave) bands, e.g., 60 GHz bands, so as toaccomplish higher data rates. To decrease propagation loss of radiowaves and increase transmission distance, beamforming, massivemultiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO),array antenna, analog beam forming, and large scale antenna techniquesare discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunderway based on advanced small cells, cloud radio access networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,coordinated multi-points (CoMP), reception-end interference cancellationand the like. In a 5G system, hybrid frequency-shift keying (FSK) andquadrature amplitude modulation (QAM) modulation (FQAM) and slidingwindow superposition coding (SWSC) as an advanced coding modulation(ACM), and filter bank multi carrier (FBMC), non-orthogonal multipleaccess (NOMA), and sparse code multiple access (SCMA) as an advancedaccess technology have been developed.

The Internet is now evolving to the Internet of things (IoT) wheredistributed entities, such as things, exchange and process informationwithout human intervention. The Internet of everything (IoE), which is acombination of the IoT technology and the big data processing technologythrough connection with a cloud server, has emerged. As technologyelements, such as sensing technology, wired/wireless communication andnetwork infrastructure, service interface technology, and securitytechnology have been demanded for IoT implementation, a sensor network,machine-to-machine (M2M) communication, machine type communication(MTC), and so forth have recently been studied. Such an IoT environmentmay provide intelligent Internet technology services that create newvalue to human life by collecting and analyzing data generated amongconnected things. IoT may be applied to a variety of fields includingsmart home, smart building, smart city, smart car or connected cars,smart grid, health care, smart appliances and advanced medical servicesthrough convergence and combination between existing informationtechnology (IT) and various industrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, MTC, and M2M communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RAN as theabove-described big data processing technology may also be considered tobe an example of convergence between the 5G technology and the IoTtechnology.

On the other hand, in the next-generation communication system, variousdiscussions for improving data processing speed have been required.

SUMMARY

An aspect of the present disclosure is to improve data processing of aterminal, in order to support services that require a high data rate anda low latency response time in a mobile communication system (e.g., anLTE or an LTE advanced (LTE-A) system).

Another aspect of the present disclosure is to provide a next-generationmobile communication system that supports a maximum data rate of 20 Gbpsin a downlink and a maximum data rate of 10 Gbps in an uplink, andrequire a very short latency response time.

Another aspect of the present disclosure is to improve the dataprocessing so as to be efficiently optimized in a case of a terminalcurrently receiving a service in a mobile communication system.

Another aspect of the present disclosure is to provide a method foraccelerating the data processing for fast processing of data beingtransmitted and received in a case of a terminal to receive a service ina next-generation mobile communication system.

Another aspect of the present disclosure is to provide anout-of-sequence deciphering method to accelerate data processing of aterminal and an apparatus for performing the out-of-sequence decipheringmethod in a mobile communication system.

Another aspect of the present disclosure is to provide anout-of-sequence deciphering method for accelerating data processing of aterminal to improve data processing speed of the terminal in a currentmobile communication system and to enable a terminal for anext-generation mobile communication system to stably receive high-speedand high-quality services having a high throughput and a low latency.

Another aspect of the present disclosure is to provide a terminal thatcan process data at a high speed when receiving and processing the data.

In accordance with an aspect of the present disclosure, a method forprocessing data by a reception device is provided. The method includesreceiving a radio link control (RLC) packet data unit (PDU);transferring an RLC service data unit (SDU) acquired from the RLC PDUfrom an RLC layer to a packet data convergence protocol (PDCP) layerregardless of a number of the RLC PDU; and deciphering the RLC SDU.

In accordance with another aspect of the present disclosure, a receptiondevice is provided. The reception device includes a transceiverconfigured to transmit and receive signals; and a controller configuredto receive an RLC PDU, transfer an RLC SDU acquired from the RLC PDUfrom an RLC layer to a PDCP layer regardless of a number of the RLC PDU,and decipher the RLC SDU.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of embodiments ofthe present disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagram of an LTE system;

FIG. 2 is a block diagram of a radio protocol structure of an LTEsystem;

FIG. 3 is a diagram of a next-generation mobile communication system;

FIG. 4 is a block diagram of a radio protocol structure of anext-generation mobile communication system;

FIG. 5 is a block diagram of a PDCP layer that takes charge of adeciphering function according to an embodiment of the presentdisclosure;

FIG. 6 is a block diagram of a process in which a terminal deciphersdata in an LTE system;

FIG. 7 is a block diagram of a deciphering method in which a receivingend of a terminal can rapidly perform a deciphering process according toan embodiment of the present disclosure;

FIG. 8 is a block diagram of an out-of-sequence deciphering method inwhich a receiving end of a terminal can perform a deciphering processcontinuously and rapidly without delay according to an embodiment of thepresent disclosure;

FIG. 9 is a block diagram of an out-of-sequence deciphering method inwhich a receiving end of a terminal can perform a deciphering processcontinuously and rapidly without delay according to an embodiment of thepresent disclosure;

FIG. 10 is a flowchart of a method of a terminal with respect to anout-of-sequence deciphering method in which a terminal of anext-generation mobile communication system can accelerate dataprocessing according to an embodiment of the present disclosure;

FIG. 11 is a flowchart of a method of a terminal with respect to anout-of-sequence deciphering method in which a terminal of anext-generation mobile communication system can accelerate dataprocessing according to an embodiment of the present disclosure;

FIG. 12 is a flowchart of a method of a reception device according to anembodiment of the present disclosure;

FIG. 13 is a block diagram of scenarios;

FIG. 14 is a block diagram of a terminal;

FIG. 15 is a block diagram of a wireless communication system;

FIG. 16 is a block diagram of a terminal; and

FIG. 17 is a block diagram of a base station in another wirelesscommunication system.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT DISCLOSURE

Hereinafter, the operation principle of the present disclosure isdescribed in detail with reference to the accompanying drawings. Indescribing the present disclosure, related well-known functions orconfigurations incorporated herein are not described in detail in a casewhere unnecessary detail would obscure the subject matter of the presentdisclosure. Further, terms described below are terms defined inconsideration of their functions in the present disclosure, but maydiffer depending on intentions of a user, an operator or customs.Accordingly, the terms are intended to be defined based on thedescription of the present disclosure.

Hereinafter, embodiments of the present disclosure are described withreference to the accompanying drawings.

Hereinafter, examples of terms for identifying a connection node,calling network entities, calling an interface between network entities,and calling various pieces of identification information are described.However, it is not intended that the present disclosure be limited tothe terms described below, but other terms for calling subjects havingequivalent meanings may be used.

Hereinafter, terms and titles that are defined in the 3rd generationpartnership project long term evolution (3GPP LTE) standards are used.However, it is not intended that the present disclosure be limited bythe terms and titles, but that the present disclosure may be equallyapplied to systems following other standards, such as 5G and new radio(NR) systems.

In an embodiment of the present disclosure, a PDCP layer may be alogical layer or a device configuration that performs an operation ofthe PDCP layer. An RLC layer may be a logical layer or a deviceconfiguration that performs an operation of the RLC layer. A mediumaccess control (MAC) layer may be a logical layer or a deviceconfiguration that performs an operation of the MAC layer. A physical(PHY) layer may be a logical layer or a device configuration thatperforms an operation of the PHY layer. Separate physical devicescorresponding to the respective layers may exist, and the operations ofthe respective layers may be controlled by at least one device (e.g., acontroller of a transmission device).

In an embodiment of the present disclosure, a device that performs aPDCP layer operation may be referred to as a PDCP device, and a devicethat performs an RLC layer operation may be referred to as an RLCdevice. Further, a device that performs a MAC layer operation may bereferred to as a MAC device.

An embodiment of the present disclosure may be applied to a receptiondevice of an LTE system or a next-generation communication system (e.g.,a 5G or an NR system). A reception device may include a terminal or abase station. A terminal may be an NR terminal, and a base station maybe an NR base station. Below, an example of a terminal is a receptiondevice. However, it is not intended that the present disclosure belimited to a terminal, but the present disclosure may be applied to theoperation of a base station.

A device that performs an RLC layer operation may receive an RLC PDUfrom a device that performs a MAC layer operation. An RLC PDU may becomposed of an RLC header and an RLC SDU. A device that performs an RLClayer operation may transfer an RLC SDU to a device that performs a PDCPlayer operation. The expression “a device that performs an RLC layeroperation transfers an RLC PDU to a device that performs an PDCP layeroperation” may be construed as a transfer of an RLC SDU corresponding toan RLC PDU.

FIG. 1 is a diagram of an LTE system.

Referring to FIG. 1, a RAN of an LTE system is composed of evolved nodeBs (ENBs) (also referred to as node Bs or base stations) 1 a-05, 1 a-10,1 a-15, and 1 a-20, a mobility management entity (MME) 1 a-25, and aserving-gateway (S-GW) 1 a-30. A user equipment (UE) or terminal 1 a-35accesses an external network through the ENBs 1 a-05 to 1 a-20 and theS-GW 1 a-30.

The ENBs 1 a-05 to 1 a-20 correspond to existing node Bs of a universalmobile telecommunications system (UMTS). An ENB is connected to the UE 1a-35 on a radio channel, and plays a more complicated role than that ofthe existing node B before LTE. In an LTE system, since all user trafficincluding a real-time service, such as voice over internet protocol(VoIP), through an internet protocol (IP) are serviced on sharedchannels, devices that performs scheduling through consolidation ofstate information, such as a buffer state, an available transmissionpower state, and a channel state of each UE, are necessary, and the ENBs1 a-05 to 1 a-20 correspond to such scheduling devices. In general, oneENB controls a plurality of cells. For example, in order to implement atransmission speed of 100 Mbps, an LTE system uses, for example,orthogonal frequency division multiplexing (OFDM) in a bandwidth of 20MHz as a radio access technology. Further, an LTE system adopts anadaptive modulation and coding (AMC) scheme that determines a modulationscheme and a channel coding rate to match a channel state of a terminal.The S-GW 1 a-30 is a device that provides a data bearer, and generatesor removes the data bearer under control of the MME 1 a-25. The MME 1a-25 is a device that takes charge of not only mobility management of aterminal but also various kinds of control functions, and is connectedto a plurality of base stations.

FIG. 2 is a block diagram of a radio protocol structure of an LTEsystem.

Referring to FIG. 2, in a UE or an ENB, a radio protocol of an LTEsystem is composed of a PDCP 1 b-05 or 1 b-40, an RLC 1 b-10 or 1 b-35,and a MAC 1 b-15 or 1 b-30, respectively. The PDCP 1 b-05 or 1 b-40takes charge of IP header compression/decompression operations. The mainfunctions of the PDCP are summarized as follows:

-   -   Header compression and decompression: robust header compression        (ROHC) only    -   Transfer of user data    -   In-sequence delivery of upper layer PDUs at a PDCP        reestablishment procedure for an RLC acknowledged mode (AM)    -   For split bearers in dual connectivity (DC) (only support for an        RLC AM): PDCP PDU routing for transmission and PDCP PDU        reordering for reception    -   Duplicate detection of lower layer SDUs at a PDCP        reestablishment procedure for an RLC AM    -   Retransmission of PDCP SDUs at handover and, for split bearers        in DC, of PDCP PDUs at a PDCP data-recovery procedure, for an        RLC AM    -   Ciphering and deciphering    -   Timer-based SDU discard in an uplink

The RLC 1 b-10 or 1 b-35 reconfigures a PDCP PDU with a proper size andperforms an automatic repeat request (ARQ) operation and the like. Themain functions of the RLC are summarized as follows:

-   -   Transfer of upper layer PDUs    -   Error correction through an ARQ (only for AM data transfer)    -   Concatenation, segmentation, and reassembly of RLC SDUs (only        for unacknowledged mode (UM) and AM data transfer)    -   Re-segmentation of RLC data PDUs (only for UM and AM data        transfer)    -   Reordering of RLC data PDUs (only for UM and AM data transfer)    -   Duplicate detection (only for UM and AM data transfer)    -   Protocol error detection (only for AM data transfer)    -   RLC SDU discard (only for UM and AM transfer)    -   RLC reestablishment

The MAC 1 b-15 or 1 b-30 is connected to several RLC layer devicesconfigured in one device (e.g., terminal or base station), and performsmultiplexing/demultiplexing of RLC PDUs into/from MAC PDU. The mainfunctions of the MAC are summarized as follows:

-   -   Mapping between logical channels and transport channels    -   Multiplexing/demultiplexing of MAC SDUs belonging to one or        different logical channels into/from transport blocks (TB)        delivered to/from the physical layer on transport channels    -   Scheduling information reporting    -   Hybrid automatic repeat request (HARQ) function (error        correction through HARQ)    -   Priority handling between logical channels of one UE    -   Priority handling between UEs by means of dynamic scheduling    -   Multimedia broadcast multicast service (MBMS) service        identification    -   Transport format selection    -   padding

The PHY 1 b-20 or 1 b-25 performs channel coding and modulation of upperlayer data to configure and transmit OFDM symbols to a radio channel, orperforms demodulation and channel decoding of the OFDM symbols receivedon the radio channel to transfer the demodulated and channel-decodeddata to an upper layer.

FIG. 3 is a diagram of a next-generation mobile communication system.

Referring to FIG. 3, a RAN of a next-generation mobile communicationsystem (e.g., NR or 5G) is composed of a new radio node B (NR gNB or NRENB) 1 c-10 and a new radio core network (NR CN) 1 c-05. A new radiouser equipment (NR UE or terminal) 1 c-15 accesses an external networkthrough the NR gNB 1 c-10 and the NR CN 1 c-05.

The NR gNB 1 c-10 corresponds to an ENB of an existing LTE system. TheNR gNB is connected to the NR UE 1 c-15 on a radio channel, and thus itcan provide a more superior service than the services of the ENB of anLTE system and an existing node B before the LTE system. Since all usertraffic is serviced on shared channels in a next-generation mobilecommunication system, a device that performs scheduling throughconsolidation of status information, such as a buffer state, anavailable transmission power state, and a channel state of each UE, isnecessary, and the NR gNB 1 c-10 takes charge of this. One NR gNBgenerally controls a plurality of cells. In order to implementultrahigh-speed data transmission as compared with the existing LTE, theNR gNB may have a maximum bandwidth that is higher than an existingbandwidth, and a beamforming technology may be additionally grafted inconsideration of OFDM as a radio connection technology. Further, an AMCscheme determining a modulation scheme and a channel coding rate tomatch the channel state of the UE is adopted. The NR CN 1 c-05 performsfunctions of mobility support, bearer configuration, and quality ofservice (QoS) configuration. The NR CN 1 c-05 may include one or aplurality of devices taking charge of not only terminal mobilitymanagement but also various kinds of control functions, and is connectedto a plurality of ENBs. Further, a next-generation mobile communicationsystem may operate with an existing LTE system, and the device includedin the NR CN 1 c-05 is connected to an MME 1 c-25 through a networkinterface. The MME 1 c-25 is connected to an ENB 1 c-30 that is an ENBof the existing LTE.

FIG. 4 is a block diagram of a next-generation mobile communicationsystem.

Referring to FIG. 4, in a UE or an NR gNB, a radio protocol of anext-generation mobile communication system includes an NR PDCP 1 d-05or 1 d-40, an NR RLC 1 d-10 or 1 d-35, and an NR MAC 1 d-15 or 1 d-30,respectively. The main function of the NR PDCP 1 d-05 or 1 d-40 mayinclude parts of the following functions:

-   -   Header compression and decompression: ROHC only    -   Transfer of user data    -   In-sequence delivery of upper layer PDUs    -   PDCP PDU reordering for reception    -   Duplicate detection of lower layer SDUs    -   Retransmission of PDCP SDUs    -   Ciphering and deciphering    -   Timer-based SDU discard in an uplink

As described above, reordering of the NR PDCP devices may indicatereordering of PDCP PDUs received from a lower layer based on PDCPsequence numbers (SNs). The reordering may include delivery of data toan upper layer in the order of reordering, recording of lost PDCP PDUsthrough reordering, status report for the lost PDCP PDUs to atransmission side, and retransmission request for the lost PDCP PDUs.The main functions of the NR RLC 1 d-10 or 1 d-35 may include parts ofthe following functions:

-   -   Transfer of upper layer PDUs    -   In-sequence delivery of upper layer PDUs    -   Out-of-sequence delivery of upper layer PDUs    -   Error correction through an ARQ    -   Concatenation, segmentation, and reassembly of RLC SDUs    -   Re-segmentation of RLC data PDUs    -   Reordering of RLC data PDUs    -   Duplicate detection    -   Protocol error detection    -   RLC SDU discard    -   RLC reestablishment

As described above, in-sequence delivery of NR RLC devices may indicatein-sequence delivery of RLC SDUs received from a lower layer to an upperlayer. In the case where one original RLC SDU is segmented into severalRLC SDUs to be received, the delivery may include reassembly anddelivery of the RLC SDUs, reordering of the received RLC PDUs based onan RLC sequence number (SN) or a PDCP SN, recording of lost RLC PDUsthrough reordering, a status report for the lost RLC PDUs to atransmission side, and a retransmission request for the lost PDCP PDUs,in-sequence delivery of only RLC SDUs just before the lost RLC SDU to anupper layer if there is a lost RLC SDU, in-sequence delivery of all RLCSDUs received before a certain timer starts to an upper layer if thetimer has expired even though there is a lost RLC SDU, or in-sequencedelivery of all RLC SDUs received to an upper layer if the timer hasexpired even though there is a lost RLC SDU. Further, the RLC PDUs maybe processed in order of reception (regardless of sequence number) andmay be transferred to a PDCP device in an out-of-sequence manner. In thecase of segments, the segments stored in a buffer or received later arereceived and reconfigured into one complete RLC PDU to be processed andtransferred to a PDCP device. An NR RLC layer may not include aconcatenation function, and the function may be performed by an NR MAClayer or may be replaced by a multiplexing function of the NR MAC layer.

As described above, an out-of-sequence delivery of an NR RLC deviceindicates a function of transferring ROC SDUs received from a lowerlayer directly to an upper layer in an out-of-sequence manner. If oneoriginal RLC SDU is segmented into several RLC SDUs to be received,delivery may include reassembly and delivery of the RLC SDUs, andrecording of lost RLC PDUs through storing and ordering of the RLC SNsor PDCP SNs of the received RLC PDUs.

The NR MAC 1 d-15 or 1 d-30 may be connected to several NR RLC layerdevices configured in one terminal, and the main functions of the NR MACmay include parts of the following functions:

-   -   Mapping between logical channels and transport channels    -   Multiplexing/demultiplexing of MAC SDUs    -   Scheduling information reporting    -   HARQ function (error correction through HARQ)    -   Priority handling between logical channels of one UE    -   Priority handling between UEs by means of dynamic scheduling    -   MBMS service identification    -   Transport format selection    -   padding

The NR PHY layer 1 d-20 or 1 d-25 may perform channel coding andmodulation of upper layer data to configure and transmit OFDM symbols toa radio channel, or may perform demodulation and channel decoding of theOFDM symbols received on the radio channel to transfer the demodulatedand channel-decoded data to an upper layer.

A device that performs the operation of each layer, such as the NR PDCPlayer, NR RLC layer, or NR MAC layer, may be a processor, a processingunit, or a processing module that performs the operation of each layer.Further, the device may be a processor, a processing unit, or aprocessing module that performs the operation of at least two layers.The processor, the processing unit, or the processing module may beincluded in a controller of the device (e.g., a terminal or a basestation).

FIG. 5 is a block diagram of a PDCP layer that takes charge of adeciphering function according to an embodiment of the presentdisclosure.

Referring to FIG. 5, a transmission side 1 e-05 of a PDCP layer performsheader compression, integrity protection 1 e-15, and ciphering 1 e-20.In contrast, a reception side 1 e-10 of the PDCP layer performs headerdecompression, integrity verification 1 e-25, and deciphering 1 e-30.The header compression and decompression, the integrity protection andverification, and the ciphering and deciphering may be performed by adevice that performs a PDCP layer operation. Integrity protection may beused to determine whether a corresponding PDCP PDU has been modified orcorrupted by anyone or for a certain reason during a delivery process atthe transmission end, and this may be identified through the integrityverification at the reception end. In contrast, ciphering is performedto prevent a hacker who maliciously intends to read information byreading the corresponding PDCP PDU, and at a normal reception end, thecontents of the PDCP PDU may be read through a deciphering process.

Ciphering and deciphering processes of a terminal are functions thatconsume a lot of data processing time and a lot of processing power ofthe terminal, and, in order to provide services with a high data rateand a low latency response time, it is necessary to continuously performciphering and deciphering processes without delay. Accordingly, anembodiment of the present disclosure provides an out-of-sequencedeciphering method in which a reception end of a terminal maycontinuously and rapidly perform a deciphering process without delay.The out-of-sequence deciphering method may be used at the reception endof the terminal. However, in the case of a service that does not requirea high data rate and a low latency response time, the terminal mayselectively interrupt the out-of-sequence deciphering method. Anout-of-sequence deciphering method is a rapid deciphering method forproviding a high data rate and a low latency response time that uses alot of processing power of the terminal and consumes a lot of batterypower. Accordingly, an out-of-sequence deciphering method may be appliedor not for each service or each bearer. Further, whether to apply anout-of-sequence deciphering method may be determined in accordance witha QoS parameter, and if it is necessary to save battery power of theterminal for a certain reason, the terminal may interrupt theout-of-sequence deciphering method.

FIG. 6 is a block diagram of a process in which a terminal deciphersdata in an LTE system.

Referring to FIG. 6, in an LTE system, a downlink in which a terminalreceives data is provided. First, operation 1 f-1 is described. In adownlink scenario, a terminal may receive data, and a device thatperforms an RLC layer operation may receive RLC PDUs from a device thatperforms a MAC layer operation, analyze RLC headers, determine sequencenumbers of the RLC PDUs, and store the RLC PDUs in an RLC buffer 1 f-10with the headers removed. The RLC buffer 1 f-10 may be a storage devicein which the device that performs the RLC layer operation stores the RLCSDUs.

In the LTE system, the device that performs the RLC layer operationsupports in-sequence delivery of RLC PDUs to the device that performsthe PDCP layer operation. Accordingly, if even one out-of-sequence RLCPDU exists, the device that performs the RLC layer operation does nottransfer any RLC PDU that may be received after the sequence number ofthe out-of-sequence RLC PDU to the device that performs the PDCP layeroperation. Accordingly, since the received RLC PDU is not transferred tothe device that performs the PDCP layer operation, the decipheringprocess may be delayed. For example, if the RLC PDUs corresponding tothe sequence numbers 1, 3, and 4 have arrived, but the RLC PDUcorresponding to the sequence number 2 has not arrived at the devicethat performs the RLC layer operation, the device that performs the RLClayer operation only transfers the RLC SDU corresponding to the sequencenumber 1 to the device that performs the PDCP layer operation.

The device that performs the PDCP layer operation may analyze the PDCPheader of the PDCP PDU (=RLC SDU), decipher a data packet throughremoval of the PDCP header, and then store the deciphered data packet ina PDCP buffer 1 f-05. The PDCP buffer 1 f-05 may be a storage device inwhich the device that performs the PDCP layer operation stores thedeciphered data packet. Thereafter, until the RLC PDU corresponding tothe sequence number 2 arrives, the device that performs the RLC layeroperation does not transfer the RLC PDUs that have already arrived tothe device that performs the PDCP layer operation. Accordingly, the RLCPDUs received by the device that has already performed the RLC layeroperation are not transferred to the device that performs the PDCP layeroperation in order to first perform the deciphering.

At operation 1 f-2, if the RLC PDU corresponding to the sequence number2 arrives at the device that performs the RLC layer operation, and thusthe sequence numbers 1, 2, 3, 4, and 5 are in sequence, the device thatperforms the RLC layer operation first transfers the RLC PDUcorresponding to the sequence number 2 from the RLC buffer 1 f-20 to thedevice that performs the PDCP layer operation in order to supportin-sequence delivery to the device that performs the PDCP layeroperation. The device that performs the RLC layer operation may transferthe RLC SDU, which is obtained by removing the header from the RLC PDUcorresponding to the sequence number 2, from the RLC buffer 1 f-20 tothe device that performs the PDCP layer operation. The device thatperforms the PDCP layer operation analyzes and removes the PDCP header,and deciphers the data packet to store the deciphered data packet in thePDCP buffer 1 f-15.

At operation 1 f-3, in the same manner described above, the device thatperforms the RLC layer operation may transfer the RLC PDU correspondingto the sequence number 3 to the device that performs the PDCP layeroperation. The device that performs the RLC layer operation may transferthe RLC SDU, which is obtained by removing the header from the RLC PDUcorresponding to the sequence number 3, from the RLC buffer 1 f-30 tothe device that performs the PDCP layer operation. The device thatperforms the PDCP layer operation deciphers the received RLC SDU, andstores the data packet in a PDCP buffer 1 f-25.

In the LTE system, the terminal supports the above-described in-sequencedelivery procedure from the device that performs the RLC layer operationto the device that performs the PDCP layer operation, and performsdeciphering based thereon. Accordingly, the deciphering process isdelayed due to the lost RLC PDUs or RLC PDUs of which transmission isdelayed.

FIG. 7 is a block diagram of a deciphering method in which a receivingend of a terminal may rapidly perform a deciphering process according toan embodiment of the present disclosure.

Referring to FIG. 7, a downlink in which a terminal receives data isprovided. First, operation 1 g-1 is described. In a downlink scenario, aterminal may receive data, and a device that performs an RLC layeroperation may receive RLC PDUs from a device that performs a MAC layeroperation, analyze RLC headers, determine sequence numbers of the RLCPDUs, and store the RLC PDUs in an RLC buffer 1 g-10 with the headersremoved.

If even one out-of-sequence RLC PDU exists in a state where the devicethat performs the RLC layer operation supports in-sequence delivery ofRLC PDUs to the device that performs the PDCP layer operation, thedevice that performs the RLC layer operation does not transfer any RLCPDU that may be received after the sequence number of theout-of-sequence RLC PDU to the PDCP device. For example, if the RLC PDUscorresponding to the sequence numbers 1, 3, and 4 have arrived, but theRLC PDU corresponding to the sequence number 2 has not arrived at thedevice that performs the RLC layer operation, the device that performsthe RLC layer operation only transfers the RLC SDU corresponding to thesequence number 1 to the device that performs the PDCP layer operation.

The device that performs the PDCP layer operation may analyze the PDCPheader of the RLC SDU (=PDCP SDU), decipher a data packet throughremoval of the PDCP header, and store the deciphered data packet in aPDCP buffer 1 g-05. Until the RLC PDU corresponding to the sequencenumber 2 arrives, the device that performs the RLC layer operation doesnot transfer the RLC PDUs that have already arrived to the device thatperforms the PDCP layer operation.

At operation 1 g-2, if the RLC PDU corresponding to the sequence number2 arrives at the device that performs the RLC layer operation, and thusthe sequence numbers 1, 2, 3, 4, and 5 are in sequence, the device thatperforms the RLC layer operation may transfer the RLC PDUs correspondingto the sequence numbers 2, 3, 4, and 5 to the device that performs thePDCP layer operation in parallel. That is, at least two of the RLC SDUscorresponding to the sequence numbers 2, 3, 4, and 5 may be transferred.The device that performs the PDCP layer operation may perform paralleldeciphering of the respective RLC SDUs received in parallel. If theterminal does not have the capability to perform parallel deciphering ofseveral RLC SDUs, the deciphering may be performed for a certain numberof RLC SDUs that can be deciphered in parallel. The number may be 1 ormore.

In the same manner, when ciphering PDCP PDUs, even the transmission endmay perform parallel ciphering of several PDCP PDUs.

As described above, the device that performs the RLC layer operationreceives the RLC PDU from the device that performs the MAC layeroperation and analyzes the RLC header, and in this case, the RLC PDU maynot include a complete RLC SDU, but may include only a segment of theRLC SDU. If the RLC PDU includes only a segment of the RLC SDU, thecorresponding RLC SDU is not transferred to the device that performs thePDCP layer operation, but it is identified whether related segmentsexist in the RLC buffer 1 g-20. If the related segments exist,reassembly thereof is performed, and if the complete RLC SDU is notconfigured, the segments are stored in the RLC buffer 1 g-20.Thereafter, if the remaining segments of the RLC SDU are received, thedevice that performs the RLC layer operation may configure one completeRLC SDU through reassembly of the segments, and may transfer thecomplete RLC SDU to the device that performs the PDCP layer operation.Accordingly, if it is determined that the RLC SDU is the segment throughanalysis of the RLC header of the RLC PDU, the deciphering process isunable to be performed rapidly. In this case, reassembly of the segmentsis performed to configure a complete RLC SDU after all the segments arereceived, and the device that performs the PDCP layer operation mayperform the deciphering procedure after receiving the complete RLC SDU.Accordingly, as illustrated in FIG. 7, since the in-sequence RLC PDUscorresponding to sequence numbers 6 and 7 are RLC PDUs corresponding tothe segments, and it is not possible to configure one complete RLC PDUthrough reassembly of the segments, the segments are stored in the RLCbuffer without being transferred to the PDCP device, and reception ofthe remaining segments must wait. Identification of whether the RLC PDUcorresponds to the segment through the RLC header may be determined, forexample, in consideration of RLC header fields related to segmentationinformation.

In an embodiment of the present disclosure, the deciphering method maybe used at the reception end of the terminal. However, if the servicedoes not require a high data rate and a low latency response time, theterminal may selectively interrupt the proposed deciphering method. Thedeciphering method is a rapid deciphering method for providing high datarate and low latency response time, which may use a lot of processingpower of the terminal and consume a lot of battery power. Accordingly,the deciphering method may be applied or not for each service or eachbearer. That is, in the case where a service requires high data rate andlow transmission delay, such as an ultra-reliable low latencycommunication (URLLC) service, high-quality audio streaming, orhigh-definition video streaming (e.g., UHD streaming), the decipheringmethod may be applied, whereas in the case where a service does notrequire high data rate and low transmission delay, the decipheringmethod may not be applied. Further, whether to apply the decipheringmethod may be determined in accordance with a QoS parameter, and if itis necessary to save battery power of a terminal for a certain reason,the terminal may interrupt the deciphering method. Further, the terminalmay determine whether to apply the deciphering method in real time basedon a certain condition. The condition may be a data rate, a transmissiondelay, a QoS parameter, a priority, or a service type, and the conditionmay be predetermined. If the condition is satisfied, the proposeddeciphering method may be performed, whereas if the condition is notsatisfied, the proposed deciphering method may not be performed.

The deciphering method described above may be applied to a terminal of acurrent LTE system and a next-generation communication system. That is,if it is intended for a terminal to receive a service having a highthroughput and a low transmission delay through an LTE system, anembodiment of the present disclosure may be applied to the terminal.Further, if it is necessary to save battery power, if theabove-described service is unnecessary, or for a certain reason, theterminal may interrupt the application of an embodiment of the presentdisclosure.

FIG. 8 is a block diagram of an out-of-sequence deciphering method inwhich a receiving end of a terminal may perform a deciphering processcontinuously and rapidly without delay according to an embodiment of thepresent disclosure. A device that performs an RLC layer operation mayprovide RLC PDUs to a device that performs a PDCP layer operationregardless of the order of sequence numbers of RLC PDUs. The detailedoperation is described below.

Referring to FIG. 8, a downlink in which a terminal receives data isprovided. In a downlink scenario, a terminal may receive data, and thedevice that performs the RLC layer operation may receive the RLC PDUsfrom the device that performs a MAC layer operation, analyze RLCheaders, determine sequence numbers of the RLC PDUs, and store the RLCPDUs in an RLC buffer 1 h-10 with the headers removed. In an embodimentof the present disclosure, even if the device that performs the RLClayer operation supports (or does not support) in-sequence delivery ofRLC PDUs to the device that performs the PDCP layer operation, thedevice that performs the RLC layer operation may first transfer theout-of-sequence RLC PDUs to the device that performs the PDCP layeroperation. That is, the device that performs the RLC layer operation maytransfer RLC SDUs obtained by removing the RLC headers from the RLC PDUsto the device that performs the PDCP layer operation. Further, thedevice that performs the PDCP layer operation may directly perform thedeciphering by analyzing and removing the PDCP headers of the RLC PDUs.That is, even if out-of-sequence RLC SDUs are received, the device thatperforms the PDCP layer operation may perform deciphering by analyzingand removing the PDCP headers. As described above, the device thatperforms the PDCP layer operation may store the PDCP sequence numbersthrough analysis of the PDCP headers. The PDCP sequence numbers maycorrespond to the sequence numbers of the RLC PDUs or RLC SDUs. Thedevice that performs the PDCP layer operation may perform in-sequencedelivery of data packets using the PDCP sequence numbers whentransferring the data packets to an upper layer.

Accordingly, in an embodiment of the present disclosure, even if thedevice that performs the RLC layer operation does not transfer the RLCPDUs or RLC SDUs in sequence, the device that performs the PDCP layeroperation may transfer them to the upper layer in sequence, and maycontinuously perform deciphering regardless of the order of sequencenumbers of the received RLC SDUs. If a speed at which the RLC SDUs comefrom the device that performs the RLC layer operation to the device thatperforms the PDCP layer operation is greater than a speed at which oneRLC SDU is deciphered, the device that performs the PDCP layer operationmay perform the deciphering by analyzing and removing in parallel thePDCP headers of the RLC SDUs, and store data packets in a PDCP buffer 1h-05. If the terminal does not have the capability to perform paralleldeciphering of several RLC SDUs, deciphering may be performed for acertain number of RLC SDUs that can be deciphered in parallel. Thenumber may be 1 or more. In the same manner as described above, whenciphering PDCP PDUs, even the transmission end (terminal or basestation) may perform parallel ciphering of several PDCP PDUs.

As described above, the device that performs the RLC layer operation mayanalyze the RLC headers of the RLC PDUs received from the MAC devicethat performs the layer operation, and transfer the RLC SDUs to thedevice that performs the PDCP layer operation regardless of the order ofthe sequence numbers (i.e., even if there are lost RLC PDUs). The devicethat performs the PDCP layer operation may directly perform decipheringof the received RLC SDUs in advance regardless of the order of thesequence numbers. For example, if the RLC PDUs corresponding to thesequence numbers 1, 3, and 4 arrive at the device that performs the RLClayer operation, the device that performs the RLC layer operation maystore the RLC SDUs in the RLC buffer 1 h-10 by analyzing and removingthe RLC headers of the RLC PDUs corresponding to the sequence numbers 1,3, and 4, and may directly transfer the RLC SDUs to the device thatperforms the PDCP layer operation again regardless of the order thereof.The device that performs the RLC layer operation may directly transferthe RLC SDUs to the device that performs the PDCP layer operationwithout storing the RLC SDUs in the RLC buffer 1 h-10. The device thatperforms the PDCP layer operation may directly decipher the received RLCSDUs, and store the deciphered data packet in the PDCP buffer 1 h-05.When the device that performs the RLC layer operation receives the RLCPDUs from the device that performs the MAC layer operation, and analyzesthe RLC headers, the RLC PDU may not include a complete RLC SDU.

If the RLC PDU includes only a segment of the complete RLC SDU, the RLCSDU corresponding to the segment is not transferred to the device thatperforms the PDCP layer operation. The device that performs the RLClayer operation identifies whether related segments exist in the RLCbuffer 1 h-10. If the related segments exist, the device performsreassembly thereof, and if the complete RLC SDU is not configured, thedevice stores the segments in the RLC buffer 1 h-10. If the complete RLCSDU is configured as the result of the reassembly, the device maytransfer the corresponding SDU to the device that performs the PDCPlayer operation regardless of the sequence number of the SDU.

Thereafter, the device that performs the RLC layer operation mayconfigure one complete RLC SDU through reassembly of the receivedremaining segments of the complete RLC SDU, and if the complete RLC SDUis configured, the device may transfer the complete RLC SDU to thedevice that performs the PDCP layer operation. Accordingly, if it isdetermined that the RLC SDU is the segment through analysis of the RLCheader, the RLC SDU is unable to be provided from the device thatperforms the RLC layer operation to the device that performs the PDCPlayer operation. Accordingly, the deciphering process is unable to beperformed rapidly. In this case, the reassembly of the segments isperformed to configure the complete RLC SDU after all the segments arereceived, and the complete RLC SDU can be transferred to the device thatperforms the PDCP layer operation. The device that performs the PDCPlayer operation can perform deciphering after receiving the complete RLCSDU.

As described above, the identification of whether the RLC SDU is thesegment through the RLC header may be determined, for example, in viewof RLC header fields related to segmentation information. As describedabove, the several RLC PDUs including the segments divided from the oneRLC SDU may have different RLC sequence numbers or may have the same RLCsequence number. This may depend on how the transmission end allocatesthe RLC sequence numbers for the segments, and in either case, it can bedetermined whether the RLC SDU is one complete RLC SDU or the segment inview of the segmentation related field of the RLC header.

In an embodiment of the present disclosure, the deciphering method maybe used at the reception end of the terminal. However, if a service doesnot require a high data rate and a low latency response time, theterminal may selectively interrupt the proposed deciphering method. Thedeciphering method is a rapid deciphering method for providing high datarate and low latency response time, which may use a lot of processingpower of the terminal and consume a lot of battery power. Accordingly,the deciphering method may be applied or not for each service or bearer.That is, in the case where a service requires high data rate and lowtransmission delay, such as a URLLC service, high-quality audiostreaming, or high-definition video streaming (e.g., UHD streaming), thedeciphering method may be applied, whereas in the case where a servicedoes not require high data rate and low transmission delay, thedeciphering method may not be applied. Further, whether to apply thedeciphering method may be determined in accordance with a QoS parameter,and if it becomes necessary to save battery power of the terminal for acertain reason, the terminal may interrupt the deciphering method.Further, the terminal may determine whether to apply the decipheringmethod in real time on a certain condition. The condition may be a datarate, a transmission delay, a QoS parameter, a priority, or a servicetype, and may be predetermined. If the condition is satisfied, theproposed deciphering method may be performed, whereas if the conditionis not satisfied, the proposed deciphering method may not be performed.The out-of-sequence deciphering method may be applied to both where theRLC device supports in-sequence delivery and does not supportin-sequence delivery, and is also applicable to a terminal of an LTEsystem.

The deciphering method as described above may be applied to a terminalof a current LTE system. That is, if it is intended for a terminal toreceive a service having high throughput and low transmission delaythrough an LTE system, an embodiment of the present disclosure may beapplied to the terminal, and may also be applied to a next-generationcommunication system. Further, if it is necessary to save battery power,if the above-described service is unnecessary, or for a certain reason,the terminal may interrupt the application of an embodiment of thepresent disclosure.

FIG. 9 is a block diagram of an out-of-sequence deciphering method inwhich a receiving end of a terminal may perform deciphering continuouslyand rapidly without delay according to an embodiment of the presentdisclosure.

Referring to FIG. 9, a downlink in which a terminal receives data isprovided. In a downlink scenario, a terminal may receive data, and thedevice that performs the RLC layer operation may receive RLC PDUs fromthe device that performs the MAC layer operation. In an embodiment ofthe present disclosure, it is proposed that the PDCP device and the RLCdevice may not use independent buffers as illustrated in FIGS. 7 and 8,but use one shared buffer. That is, the PDCP device and the RLC devicemay share one buffer (e.g., a flash memory).

If the RLC PDUs are received from the device that performs the MAC layeroperation, the device that performs the RLC layer operation, atoperation 1 i-10, may analyze and remove the RLC headers from thereceived RLC PDUs, and provide RLC SDUs (=PDCP PDUs) to the device thatperforms the PDCP layer operation. The device that performs the PDCPlayer operation, at operation 1 i-15, may decipher the RLC SDUs andstore the deciphered RLC SDUs in a shared buffer 1 i-05.

For example, procedures before storing the RLC SDUs in the shared buffer1 i-05 may be performed on a dynamic random access memory (DRAM).Further, if a speed at which the device that performs the MAC layeroperation transfers the RLC PDU to the device that performs the RLClayer operation, is greater than a speed at which one RLC PDU isreceived, the RLC header is analyzed and removed from the RLC PDU, andthe RLC SDU (PDCP PDU) is deciphered and stored in the shared buffer,the above-described procedures may be performed in parallel with respectto the RLC SDUs. If the terminal does not have the capability to performparallel deciphering of several RLC SDUs, deciphering may be performedfor a certain number of RLC SDUs that can be deciphered in parallel. Thenumber may be 1 or more. In the same manner, when ciphering PDCP PDUs,even the transmission end (terminal or base station) may performparallel ciphering of several PDCP PDUs.

In an embodiment of the present disclosure, the out-of-sequencedeciphering method according to the present disclosure, as compared withthe second embodiment, since the device that performs the PDCP layeroperation and the device that performs the RLC layer operation share thebuffer, the number of memory accesses occurring when processing andstoring data can be reduced, and the buffer can be managed moreefficiently. Accordingly, it is possible to obtain a greater dataprocessing speed. Further, the out-of-sequence deciphering method may beapplied to a case where the RLC device supports in-sequence delivery, acase where the RLC device does not support in-sequence delivery, and toa terminal of an LTE system.

When the device that performs the RLC layer operation receives the RLCPDUs from the device that performs the MAC layer operation, and analyzesthe RLC headers, the RLC PDU may not include a complete RLC SDU, but mayinclude only a segment of the complete RLC SDU. In this case, the RLCSDU corresponding to the segment is not transferred to the device thatperforms the PDCP layer operation. If the device that performs the RLClayer operation identifies whether related segments exist in the RLCbuffer, it performs reassembly thereof, and if the complete RLC SDU isnot configured, it stores the segments in the RLC buffer. Thereafter,the device that performs the RLC layer operation may configure onecomplete RLC SDU through reassembly of the received remaining segmentsof the complete RLC SDU, and may transfer the complete RLC SDU to thedevice that performs the PDCP layer operation.

Accordingly, if it is determined that the RLC SDU is the segment throughanalysis of the RLC header, deciphering is unable to be performedrapidly. In this case, reassembly of the segments is performed toconfigure the complete RLC SDU after all the segments are received, andthe complete RLC SDU may be transferred to the device that performs thePDCP layer operation. The device that performs the PDCP layer operationmay perform deciphering after receiving the complete RLC SDU. Asdescribed above, identification of whether the RLC SDU is a segmentthrough the RLC header may be determined, for example, in view of RLCheader fields related to segmentation information. As described above,several RLC PDUs including segments divided from one RLC SDU may havedifferent RLC sequence numbers or the same RLC sequence number. This maydepend on how the transmission end allocates the RLC sequence numbersfor the segments, and in either case, it can be determined whether theRLC SDU is one complete RLC SDU or a segment in view of the segmentationrelated field of the RLC header.

In an embodiment of the present disclosure, the deciphering method maybe used at the reception end of the terminal. However, if the servicedoes not require a high data rate and a low latency response time, theterminal may selectively interrupt the deciphering method. Thedeciphering method is a rapid deciphering method for providing high datarate and low latency response time, which may use a lot of processingpower of the terminal and consume a lot of battery power. Accordingly,the deciphering method may or not be applied for each service or bearer.That is, in a case where a service requires high data rate and lowtransmission delay, such as a URLLC service, high-quality audiostreaming, or high-definition video streaming (e.g., UHD streaming), thedeciphering method may be applied, whereas in a case where a servicedoes not require high data rate and low transmission delay, thedeciphering method may not be applied.

Further, whether to apply the deciphering method may be determined inaccordance with a QoS parameter, and if it becomes necessary to savebattery power of the terminal for a certain reason, the terminal mayinterrupt the deciphering method. Further, the terminal may determinewhether to apply the deciphering method in real time based on a certaincondition. The condition may be a data rate, a transmission delay, a QoSparameter, a priority, or a service type, and may be predetermined. Ifthe condition is satisfied, the deciphering method may be performed,whereas if the condition is not satisfied, the deciphering method maynot be performed. In an embodiment of the present disclosure, theout-of-sequence deciphering method may be applied to a case where theRLC device supports in-sequence delivery, a case where the RLC devicedoes not support in-sequence delivery, and to a terminal of an LTEsystem.

The deciphering method described above may be applied to a terminal of acurrent LTE system. That is, if a terminal is to receive a servicehaving a high throughput and a low transmission delay through an LTEsystem, an embodiment of the present disclosure may be applied to theterminal. Further, if it is necessary to save battery power, if theabove-described service is unnecessary, or for a certain reason, theterminal may interrupt the application of the embodiment of the presentdisclosure.

FIG. 10 is a flowchart of an operation of a terminal with respect to anout-of-sequence deciphering method in which a terminal of anext-generation mobile communication system may accelerate dataprocessing according to an embodiment of the present disclosure.

Referring to FIG. 10, a downlink in which a terminal receives data in anext-generation mobile communication system is provided. In a downlinkscenario, the terminal receives data, and at operation 1 j-05, thedevice that performs an RLC layer operation receives RLC PDUs from thedevice that performs a MAC layer operation.

At operation 1 j-10, the device that performs the RLC layer operationanalyzes RLC headers, determines sequence numbers of the RLC PDUs, andidentifies segmentation related RLC header fields to determine whetherthe RLC PDUs are complete RLC SDUs (or complete RLC PDUs) or segments.If the RLC PDUs are determined to be complete RLC PDUs at operation 1j-10, the method proceeds to operation 1 j-15, whereas if the RLC PDUsare not complete RLC PDUs, the method proceeds to operation 1 j-25.

If the RLC PDUs are complete RLC PDUs, the device that performs the RLClayer operation may directly remove RLC headers and may transfer RLC SDU(=PDCP PDU) to the device that performs the PDCP layer operation even ifthere are out-of-sequence RLC PDUs at operation 1 j-15. At operation 1j-20, the device that performs the PDCP layer operation may analyze andremove the PDCP header from the received PDCP PDU, perform deciphering,and store data packets in a PDCP buffer. Further, if a speed at whichthe RLC SDUs come from the device that performs the RLC layer operationto the device that performs the PDCP layer operation is greater than aspeed at which one RLC SDU is deciphered, the device may performdeciphering of the RLC SDUs in parallel, analyze and remove the PDCPheaders from the RLC SDUs, and store data packets in the PDCP buffer. Ifthe terminal does not have the capability to perform paralleldeciphering of several RLC SDUs, deciphering may be performed for acertain number of RLC SDUs that can be deciphered in parallel. Thenumber may be 1. For example, if the RLC PDUs corresponding to thesequence numbers 1, 3, and 4 arrive at the device that performs the RLClayer operation, the device that performs the RLC layer operation maystore the RLC SDUs in the buffer by analyzing and removing the RLCheaders of the RLC PDUs corresponding to the sequence numbers 1, 3, and4, and may transfer the RLC SDUs to the device that performs the PDCPlayer operation again. The device that performs the PDCP layer operationdeciphers the received RLC SDUs and stores the data packet in the PDCPbuffer.

At operation 1 j-10, the device that performs the RLC layer operationreceives the RLC PDU from the device that performs the MAC layeroperation, and analyzes the RLC header. In this case, if the RLC PDUdoes not include a complete RLC SDU, but includes only a segment of theRLC SDU, the RLC SDU corresponding to the segment is not transferred tothe device that performs the PDCP layer operation.

At operation 1 j-25, the device that performs the RLC layer operationidentifies whether related segments exist in the buffer. If the relatedsegments do not exist, the device may wait for reception of the nextsegments. If the related segments exist in the buffer, the methodproceeds to operation 1 j-30 to perform reassembly thereof. If thecomplete RLC SDU does not result from performing reassembly, the devicemay store the segments in the RLC buffer. Thereafter, the remainingsegments of the complete RLC SDU may be received, and one complete RLCSDU may result from reassembly of the received segments.

At operation 1 j-35, the device that performs the RLC layer operationidentifies whether the reassembled segments form a complete RLC SDU or acomplete RLC PDU. If the reassembled segments form a complete RLC SDU,the method proceeds to operation 1 j-40, otherwise the method proceedsto operation 1 j-25.

At operation 1 j-40, the device that performs the RLC layer operationremoves the RLC header from the complete RLC PDU, and transfers the RLCSDU to the device that performs the PDCP layer operation. At operation 1j-45, the device that performs the PDCP layer operation analyzes andremoves the PDCP header from the received PDCP PDU, performsdeciphering, and stores a data packet in the PDCP buffer.

Accordingly, if it is determined that the RLC SDU is a segment throughanalysis of the RLC header, deciphering is unable to be performedrapidly. In this case, the reassembly of the segments is performed toconfigure the complete RLC SDU after all the segments are received, andthen deciphering is performed with respect to the complete RLC SDU. Asdescribed above, the identification of whether the RLC SDU is a segmentthrough the RLC header may be determined, for example, in view of RLCheader fields related to segmentation information. That is, in anembodiment of the present disclosure, the RLC SDU may be provided to thedevice that performs the PDCP layer operation regardless of the sequencenumber of the RLC PDU or RLC SDU. However, if the RLC PDU or RLC SDU isa segment, the RLC PDU or RLC SDU is unable to be provided to the devicethat performs the PDCP layer operation until the segments arereassembled to form the complete RLC PDU or the complete RLC SDU.

FIG. 11 is a flowchart of a method of an operation of a terminal withrespect to an out-of-sequence deciphering method in which a terminal ofa next-generation mobile communication system may accelerate dataprocessing according to an embodiment of the present disclosure.

Referring to FIG. 11, a downlink in which a terminal receives data inthe next-generation mobile communication system is provided. In adownlink scenario, the terminal receives data, and at operation 1 k-05,the device that performs the RLC layer operation receives RLC PDUs fromthe device that performs the MAC layer operation.

In a downlink scenario, a terminal may receive data, and the device thatperforms the RLC layer operation may receive RLC PDUs from the devicethat performs the MAC layer operation. In an embodiment of the presentdisclosure, the device that performs the PDCP layer operation and thedevice that performs the RLC layer operation do not use independentbuffers as illustrated in FIGS. 7 and 8, but use one shared buffer. Thatis, the device that performs the PDCP layer operation and the devicethat performs the RLC layer operation may share one buffer (e.g., aflash memory).

If the RLC PDUs are received from the device that performs the MAC layeroperation, the terminal, at operation 1 k-10, analyzes the RLC headersof the received RLC PDUs, determines the sequence numbers of the RLCPDUs, and identifies segment information related RLC header fields toidentify whether the received RLC PDU is a complete RLC PDU (or completeRLC SDU) or a segment. If the RLC PDU is identified as a complete RLCPDU at operation 1 k-10, the method proceeds to operation 1 k-15,otherwise the method proceeds to operation 1 k-20.

If the RLC PDUs are the complete RLC PDUs as described above, the devicethat performs the RLC layer operation removes the RLC headers andtransfers the RLC PDUs to the device that performs the PDCP layeroperation at operation 1 k-15. The device that performs the PDCP layeroperation may decipher the RLC SDU (PDCP PDU) and may directly store thedeciphered RLC SDU (PDCP PDU) in the shared buffer. That is, theprocedures before storing the RLC SDU (PDCP PDU) may be performed on aDRAM of the terminal. Further, if a speed at which the MAC devicetransfers the RLC PDU to the RLC device is greater than a speed at whichone RLC PDU is received, the RLC header is analyzed and removed from thereceived RLC PDU, and the RLC SDU (PDCP PDU) is deciphered and stored inthe shared buffer, where the above-described procedures may be performedin parallel with respect to the RLC SDUs.

At operation 1 k-10, if the RLC PDU does not include the complete RLCSDU, but includes only a segment of the RLC SDU when the device thatperforms the RLC layer operation receives the RLC PDU from the devicethat performs the MAC layer operation and analyzes the RLC header, theRLC SDU corresponding to the segment is not transferred to the devicethat performs the PDCP layer operation. Accordingly, the device thatperforms the PDCP layer operation does not perform deciphering.

At operation 1 k-20, the device that performs the RLC layer operationidentifies whether related segments exist in the buffer. If the relatedsegments do not exist in the buffer, the device may wait for thereception of the next segments. If the related segments exist in thebuffer, the device proceeds to operation 1 k-25 to perform reassembly ofthe segments. If the complete RLC SDU is not formed as the result of thereassembly, the device may store the segments in the buffer. Thereafter,if the remaining segments of the complete RLC SDU are received, thedevice that performs the RLC layer operation may configure one completeRLC SDU through reassembly of the received segments.

At operation 1 k-30, the device that performs the RLC layer operationidentifies whether the reassembled segments form a complete RLC SDU or acomplete RLC PDU. If the reassembled segments form the complete RLC SDU,the device proceeds to operation 1 k-35. At operation 1 k-35, the devicethat performs the RLC layer operation removes the header from the RLCPDU and transfers the RLC SDU to the device that performs the PDCP layeroperation, and the device that performs the PDCP layer operation mayremove the PDCP header from the PDCP PDU, decipher a data packet, andstore the deciphered data packet in the buffer.

If it is determined that the RLC SDU is a segment through analysis ofthe RLC header as described above, reassembly of the segments isperformed to form the complete RLC SDU after all the segments arereceived, and then deciphering is performed. As described above, theidentification of whether the RLC SDU is a segment through the RLCheader may be determined, for example, in view of RLC header fieldsrelated to segmentation information. That is, in an embodiment of thepresent disclosure, the RLC SDU may be provided to the device thatperforms the PDCP layer operation regardless of the sequence number ofthe RLC PDU or RLC SDU. However, if the RLC PDU or RLC SDU is a segment,the RLC PDU or RLC SDU is unable to be provided to the device thatperforms the PDCP layer operation until the segments are reassembled toform the complete RLC PDU or the complete RLC SDU.

FIG. 12 is a flowchart of an operation of a reception device accordingto an embodiment of the present disclosure.

Referring to FIG. 12, at operation 1 k-50, a reception device mayreceive an RLC PDU. An RLC layer of the reception device may receive aPDU. A device that performs an RLC layer operation may receive the RLCPDU from a device that performs the MAC layer operation. The device thatperforms the RLC layer operation may analyze an RLC header of thereceived RLC PDU, and may identify the RLC PDU number or a sequencenumber from the RLC header. The device that performs the RLC layeroperation may store an RLC SDU that is obtained by removing the RLCheader from the RLC PDU in a buffer. The buffer may be an RLC buffer ora shared buffer.

At operation 1 k-55, the RLC SDU may be transferred from the RLC layerto the PDCP layer. The device that performs the RLC layer operation maytransfer the RLC SDU to the device that performs the PDCP layeroperation. The RLC SDU conceptually corresponds to the PDCP PDU. In anembodiment of the present disclosure, the device that performs the RLClayer operation may transfer the RLC SDU. If an out-of-sequence RLC SDUis received, the device that performs the RLC layer operation mayprocess the RLC SDU according to an embodiment of the presentdisclosure. The device that performs the RLC layer operation maysimultaneously transfer in-sequence RLC SDUs to the PDCP layer. Thedevice that performs the RLC layer operation may transfer the RLC SDU tothe PDCP layer regardless of the number of the RLC SDU. The device thatperforms the RLC layer operation may operate a shared buffer with thedevice that performs the PDCP layer operation. On the other hand, if theRLC SDU received by the device that performs the RLC layer operation isnot a complete RLC SDU, but is a segment of the RLC SDU, the device thatperforms the RLC layer operation may not transfer the RLC SDU to thedevice that performs the PDCP layer operation until reassembly isperformed to form the complete RLC SDU.

At operation 1 k-60, the device that performs the PDCP layer operationmay receive the RLC SDU from the device that performs the RLC layeroperation. The PDCP layer construes the RLC SDU as the PDCP PDU. Thedevice that performs the PDCP layer operation may decipher the PDCP PDU.The device that performs the PDCP layer operation may analyze and removethe PDCP header, and decipher the PDCP SDU packet. The device thatperforms the PDCP layer operation may store the deciphered data packetin the PDCP buffer. In the case of using a shared buffer, the device maystore the deciphered data packet in the shared buffer. The device thatperforms the PDCP layer operation may decipher the data included in thereceived RLC SDU regardless of the RLC SDU number or the sequencenumber.

Through the above-described method, since the RLC SDU may be rapidlytransferred up to the PDCP layer and rapid deciphering is possible evenin the PDCP layer, the data deciphering and the reception speed may beimproved.

The respective operations may be or may not be performed in accordancewith certain conditions, and the conditions may be the same as thosedescribed above.

FIG. 13 is a block diagram of certain scenarios.

Referring to FIG. 13, 1 l-01 is a scenario in which a terminal receivesa service from an LTE base station, and 1 l-02 is a scenario in which aterminal receives a service through dual connectivity between LTE basestations. In addition, 1 l-03 is a scenario in which in tri-band carrieraggregation or 3C type operation between an LTE base station and an NRbase station, the LTE base station is a master cell group (MCG), and theNR base station is a secondary cell group (SCG), and 1 l-04 indicates ascenario in which in 3C type operation between an LTE base station andan NR base station, the NR base station is an MCG, and the LTE basestation is an SCG. Further, 1 l-05 is a scenario in which in 3C typeoperation between a first NR base station and a second NR base station,the first NR base station is an MCG, and the second NR base station isan SCG, and 1 l-06 is a scenario in which a terminal receives a servicefrom one NR base station. Even in scenarios such as 1 l-01, 1 l-02, 1l-03, 1 l-04, 1 l-05, and 1 l-06, an embodiment or a combination ofembodiments of the present disclosure described above may be applied toa data process for receiving a service from an LTE base station, an NRbase station, or all base stations. Further, embodiments or acombination of embodiments are also applicable to variousmulti-connectivity scenarios.

Further, embodiments of the present disclosure are applicable to atransparent mode (TM), an unacknowledged mode (UM), and an acknowledgedmode (AM).

FIG. 14 is a block diagram of a terminal 1400 according to an embodimentof the present disclosure. Referring to FIG. 14, the terminal 1400includes a transceiver 1 m-05, a controller 1 m-10, amultiplexer/demultiplexer 1 m-20, a control message processor 1 m-35,various kinds of upper layer devices 1 m-25 and 1 m-30, an EPS bearermanager 1 m-40, and a non-access stratum (NAS) layer device 1 m-45.

The transceiver 1 m-05 receives data and a certain control signal on aforward channel of a serving cell, and transits the data and the controlsignal on a backward channel. If a plurality of serving cells areconfigured, the transceiver 1 m-05 performs data transmission/receptionand control signal transmission/reception through the plurality ofserving cells.

The multiplexer/demultiplexer 1 m-20 serves to multiplex data generatedby the upper layer devices 1 m-25 and 1 m-30 or the control messageprocessor 1 m-35, to demultiplex the data received through thetransceiver 1 m-05, and to properly transfer the multiplexed ordemultiplexed data to the upper layer devices 1 m-25 and 1 m-30 or thecontrol message processor 1 m-35.

The control message processor 1 m-35 is a radio resource control (RRC)layer device, and takes a necessary operation through processing acontrol message received from a base station. For example, if an RRCconnection setup message is received, the control message processor 1m-35 sets signaling radio bearer 1 (SRB1) and temporary data radiobearer (DRB).

The upper layer device 1 m-25 or 1 m-30 indicates a DRB device, and maybe configured for each service. The upper layer device 1 m-25 or 1 m-30processes data generated through a user service, such as a file transferprotocol (FTP) or VoIP, and transfers the processed data to themultiplexer/demultiplexer 1 m-20, or processes data transferred from themultiplexer/demultiplexer 1 m-20 and transfers the processed data to aservice application of an upper layer. One service may be mapped ontoone evolved packet system (EPS) bearer and one upper layer device in aone-to-one manner. If a certain EPS bearer uses a data transferprocedure (e.g., one of the embodiments of the present disclosure) ofthe present disclosure, the upper layer device 1 m-25 or 1 m-30 is notconfigured with respect to the corresponding EPS bearer.

The controller 1 m-10 controls the transceiver 1 m-05 and themultiplexer/demultiplexer 1 m-20 to identify scheduling commands, forexample, backward grants, received through the transceiver 1 m-05 andperform backward transfer thereof as proper transfer resources at aproper time.

The EPS bearer manager determines whether to apply the data transferprocedure, and if such data transfer procedure is applied, it transfersan IP packet to the RRC layer device or the temporary DRB device.

FIG. 15 is a block diagram of a wireless communication system 1500.

Referring to FIG. 15, a block diagram of a base station, an MME, and anS-GW is illustrated. The base station includes a transceiver 1 n-05, acontroller 1 n-10, a multiplexer/demultiplexer 1 n-20, a control messageprocessor 1 n-35, various kinds of upper layer devices 1 n-25 and 1n-30, a scheduler 1 n-15, EPS bearer devices 1 n-40 and 1 n-45, and aNAS layer device 1 n-50. The EPS bearer device is located in the S-GW,and the NAS layer device is located in the MME.

The transceiver 1 n-05 transmits data and a certain control signal on aforward carrier, and receives the data and the control signal on abackward carrier. If a plurality of carriers are configured, thetransceiver 1 n-05 performs data transmission/reception and controlsignal transmission/reception on the plurality of carriers.

The multiplexer/demultiplexer 1 n-20 serves to multiplex data generatedby the upper layer devices 1 n-25 and 1 n-30 or the control messageprocessor 1 n-35, demultiplex the data received through the transceiver1 n-05, and properly transfer the multiplexed or demultiplexed data tothe upper layer devices 1 n-25 and 1 n-30, the control message processor1 n-35, or the controller 1 n-10. The control message processor 1 n-35may be configured for each EPS bearer, and configures the datatransferred from the EPS bearer device as an RLC PDU to transfer theconfigured RLC PDU to the multiplexer/demultiplexer 1 n-20 or configuresthe RLC PDU transferred from the multiplexer/demultiplexer 1 n-20 as aPDCP SDU to transfer the configured PDCP SDU to the EPS bearer device.

The scheduler 1 n-15 allocates a transfer resource to the terminal at aproper time in consideration of a buffer state and a channel state ofthe terminal, and controls the transceiver to process a signaltransmitted by the terminal or to transmit the signal to the terminal.

The EPS bearer device 1 n-40 or 1 n-45 is configured for each EPSbearer, and processes data transferred from the upper layer device totransfer the processed data to a next network node.

The upper layer device 1 n-25 or 1 n-30 and the EPS bearer device 1 n-40are mutually connected by an S1-U bearer. The upper layer device 1 n-25and 1 n-30 corresponding to a common DRB is connected by the EPS bearerfor the common DRB and a common S1-U bearer.

The NAS layer device 1 n-50 processes an IP packet provided in a NASmessage to transfer the processed IP packet to the S-GW.

FIG. 16 is a block diagram of a terminal 1600.

Referring to FIG. 16, the terminal 1600 includes a radio frequency (RF)processor 1 o-10, a baseband processor 1 o-20, a storage unit 1 o-30,and a controller 1 o-40. The terminal 1600 may be composed of acontroller 1 o-40 and a transceiver. In this case, the controller 1 o-40may include at least one processor.

The RF processor 1 o-10 performs a function for transmitting andreceiving a signal on a radio channel, such as signal band conversionand amplification. That is, the RF processor 1 o-10 performsup-conversion of a baseband signal provided from the baseband processor1 o-20 into an RF-band signal to transmit the converted signal to anantenna, and performs down-conversion of the RF-band signal receivedthrough the antenna into a baseband signal. For example, the RFprocessor 1 o-10 may include a transmission filter, a reception filter,an amplifier, a mixer, an oscillator, a digital-to-analog converter(DAC), and an analog-to-digital converter (ADC). Although only oneantenna is illustrated in FIG. 16, the terminal 1600 may be providedwith a plurality of antennas. Further, the RF processor 1 o-10 mayinclude a plurality of RF chains. Further, the RF processor 1 o-10 mayperform beamforming. For beamforming, the RF processor 1 o-10 may adjustphases and sizes of signals transmitted or received through theplurality of antennas or antenna elements. Further, the RF processor 1o-10 may perform MIMO, and may receive several layers during theperformance of a MIMO operation. The RF processor 1 o-10 may performreception beam sweeping through a proper configuration of a plurality ofantennas or antenna elements under the control of the controller 1 o-40,or may control the direction and the beam width of the reception beam sothat the reception beam is synchronized with the transmission beam. Thebaseband processor 1 o-20 performs conversion between a baseband signaland a bit string in accordance with a physical layer standard of thesystem. For example, during data transmission, the baseband processor 1o-20 generates complex symbols by encoding and modulating a transmittedbit string. Further, during data reception, the baseband processor 1o-20 restores a received bit string by demodulating and decoding thebaseband signal provided from the RF processor 1 o-10. For example, inthe case of following an OFDM method, during data transmission, thebaseband processor 1 o-20 generates complex symbols by encoding andmodulating a transmitted bit string, performs mapping of the complexsymbols on subcarriers, and then configures OFDM symbols through aninverse fast Fourier transform (IFFT) operation and cyclic prefix (CP)insertion. Further, during data reception, the baseband processor 1 o-20divides the baseband signal provided from the RF processor 1 o-10 in theunit of OFDM symbols, restores the signals mapped on the subcarriersthrough a fast Fourier transform (FFT) operation, and then restores thereceived bit string through demodulation and decoding.

The baseband processor 1 o-20 and the RF processor 1 o-10 transmit andreceive the signals as described above. Accordingly, the basebandprocessor 1 o-20 and the RF processor 1 o-10 may be referred to as atransmitter, a receiver, a transceiver, or a communication unit.Further, in order to support different radio connection technologies, atleast one of the baseband processor 1 o-20 and the RF processor 1 o-10may include a plurality of communication modules. Further, in order toprocess signals of different frequency bands, at least one of thebaseband processor 1 o-20 and the RF processor 1 o-10 may includedifferent communication modules. For example, the different radioconnection technologies may include an LTE network and an NR network.Further, the different frequency bands may include super high frequency(SHF) (e.g., 2.5 GHz or 5 GHz) band and millimeter wave (mmWave) (e.g.,60 GHz) band.

The storage unit 1 o-30 stores a basic program for an operation of theterminal 1600, application programs, and data of configurationinformation. The storage unit 1 o-30 provides stored data in accordancewith a request from the controller 1 o-40.

The controller 1 o-40 controls the entire operation of the terminal1600. For example, the controller 1 o-40 transmits and receives signalsthrough the baseband processor 1 o-20 and the RF processor 1 o-10.Further, the controller 1 o-40 records or reads data in or from thestorage unit 1 o-30. For this, the controller 1 o-40 may include atleast one multi-connection processor 1 o-42. For example, the controller1 o-40 may include a communication processor that performs a control forcommunication and an application processor controlling an upper layer,such as an application program.

In an embodiment of the present disclosure, the controller 1 o-40 may bea device that performs operations of respective layers, such as a PDCPlayer, an RLC layer, and a MAC layer, and may include at least one of aprocessor, a processing unit, and a processing module that performrespective layer operations. In an embodiment of the present disclosure,expressions of a device that performs a PDCP layer operation, a devicethat performs an RLC layer operation, a device that performs a MAC layeroperation, and a device that performs a PHY layer operation have beenused. However, the present disclosure is not intended to be limitedthereto. Accordingly, the devices that perform the operations of therespective layers may be independent entities or entities that performtwo or more layer operations. Although the operations of the respectivelayers may be logically discriminated, the controller 1 o-40 may controlthe operations of the respective logical layers.

In an embodiment of the present disclosure, the controller 1 o-40 mayoperate to receive an RLC PDU, to transfer an RLC SDU acquired from theRLC PDU from the RLC layer to the PDCP layer regardless of the RLC PDUnumber, and to decipher the RLC SDU. Further, the controller 1 o-40 mayoperate to transfer the RLC PDU to the PDCP layer even if the RLC PDUnumber is not in sequence with the preprocessed RLC PDU number.

Further, the controller 1 o-40 may operate to remove the RLC header ofthe RLC PDU, to store the RLC SDU in a buffer, and to transfer the RLCSDU stored in the buffer to the PDCP layer even if the number of the RLCSDU stored in the buffer is not in sequence with the number of thepreprocessed RLC SDU. Further, if the RLC SDU is transferred, thecontroller 1 o-40 may operate to decipher the PDCP PDU regardless of thenumber of the PDCP PDU acquired from the RLC SDU.

Further, the controller 1 o-40 may operate to determine whether the RLCSDU is a complete RLC SDU or a segment of the RLC SDU, and if the RLCSDU is not a complete RLC SDU, it may operate not to transfer the RLCSDU to the PDCP layer. Further, if the RLC SDU is a segment of the RLCSDU, the controller 1 o-40 may operate to determine whether a second RLCSDU related to the RLC SDU is stored in the buffer.

Further, if the second RLC SDU is stored, the controller 1 o-40 mayoperate to combine the RLC SDU and the second RLC SDU to transfer thecombined RLC SDUs to the PDCP layer, whereas if the second RLC SDU isnot stored, the controller may operate to wait for reception of thesecond RLC SDU.

Further, if the RLC SU that is in sequence with the RLC SDU is stored inthe buffer, the controller 1 o-40 may operate to simultaneously transferthe RLC SDU and the RLC SDU that is in sequence with the RLC SDU to thePDCP layer.

Further, the controller 1 o-40 may operate so that the RLC layer and thePDCP layer use a shared buffer.

FIG. 17 is a block diagram of a base station 1700 in a wirelesscommunication system.

Referring to FIG. 17, the base station 1700 includes an RF processor 1p-10, a baseband processor 1 p-20, a backhaul communication unit 1 p-30,a storage unit 1 p-40, and a controller 1 p-50.

The RF processor 1 p-10 performs a function for transmitting andreceiving a signal on a radio channel, such as signal band conversionand amplification. That is, the RF processor 1 p-10 performsup-conversion of a baseband signal provided from the baseband processor1 p-20 into an RF-band signal to transmit the converted signal to anantenna, and performs down-conversion of the RF-band signal receivedthrough the antenna into a baseband signal. For example, the RFprocessor 1 p-10 may include a transmission filter, a reception filter,an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although onlyone antenna is illustrated in FIG. 17, the first connection node may beprovided with a plurality of antennas. Further, the RF processor 1 p-10may include a plurality of RF chains. Further, the RF processor 1 p-10may perform beamforming. For the beamforming, the RF processor 1 p-10may adjust phases and sizes of signals transmitted or received throughthe plurality of antennas or antenna elements. Further, the RF processor1 p-10 may perform down MIMO operation through transmission of one ormore layers.

The baseband processor 1 p-20 performs conversion between a basebandsignal and a bit string in accordance with a physical layer standard ofthe first radio connection technology. For example, during datatransmission, the baseband processor 1 p-20 generates complex symbols byencoding and modulating a transmitted bit string. Further, during datareception, the baseband processor 1 p-20 restores a received bit stringby demodulating and decoding the baseband signal provided from the RFprocessor 1 p-10. For example, in the case of following an OFDM method,during data transmission, the baseband processor 1 p-20 generatescomplex symbols by encoding and modulating a transmitted bit string,performs mapping of the complex symbols on subcarriers, and thenconfigures OFDM symbols through the IFFT operation and CP insertion.Further, during data reception, the baseband processor 1 p-20 dividesthe baseband signal provided from the RF processor 1 p-10 in the unit ofOFDM symbols, restores the signals mapped on the subcarriers through theFFT operation, and then restores the received bit string throughdemodulation and decoding. The baseband processor 1 p-20 and the RFprocessor 1 p-10 transmit and receive the signals as described above.Accordingly, the baseband processor 1 p-20 and the RF processor 1 p-10may be referred to as a transmitter, a receiver, a transceiver, acommunication unit, or a wireless communication unit.

The backhaul communication unit 1 p-30 provides an interface for thatperforms communication with other nodes in the network.

The storage unit 1 p-40 stores therein a basic program for an operationof the main base station 1700, application programs, and data ofconfiguration information. In particular, the storage unit 1 p-40 maystore information on a bearer allocated to the connected terminal andthe measurement result reported from the connected terminal. Further,the storage unit 1 p-40 may store information that becomes a basis ofdetermination whether to provide or suspend a multi-connection to theterminal. Further, the storage unit 1 p-40 provides stored data inaccordance with a request from the controller 1 p-50.

The controller 1 p-50 controls the whole operation of the main basestation 1700. For example, the controller 1 p-50 transmits and receivessignals through the baseband processor 1 p-20 and the RF processor 1p-10 or through the backhaul communication unit 1 p-30. Further, thecontroller 1 p-50 records or reads data in or from the storage unit 1p-40. For this, the controller 1 p-50 may include at least onemulti-connection processor 1 p-52.

In an embodiment of the present disclosure, the controller 1 p-50 may bea device that performs operations of respective layers, such as a PDCPlayer, an RLC layer, and a MAC layer, and may include at least one of aprocessor, a processing unit, and a processing module that performrespective layer operations. In an embodiment of the present disclosure,a device that performs a PDCP layer operation, a device that performs anRLC layer operation, a device that performs a MAC layer operation, and adevice that performs a PHY layer operation have been used. However, thepresent disclosure is not intended to be limited thereto. Accordingly,the devices that perform the operations of the respective layers may beindependent entities or entities that perform two or more layeroperations. Although the operations of the respective layers may belogically discriminated, the controller 1 p-50 may control theoperations of the respective logical layers.

In an embodiment of the present disclosure, since the operation of thebase station 1700 as the reception device corresponds to the operationof the terminal 1600 as the reception device, the controller 1 p-50 ofthe base station 1700 performs the same operation as the operation ofthe terminal controller 1 o-40 as described above with reference to FIG.16.

Although embodiments of the present disclosure have been described abovewith reference to the accompanying drawings and certain terms have beenused, these are merely used as examples to assist those of ordinaryskill in the art to gain a comprehensive understanding of the presentdisclosure, but are not intended to limit the scope of the presentdisclosure. It will be apparent to those of ordinary skill in the art towhich the present disclosure pertains that various modifications arepossible based on the present disclosure in addition to the embodimentsdisclosed herein without departing from the scope of the presentdisclosure as defined by the appended claims and their equivalents.

What is claimed is:
 1. A method for processing data by a receptiondevice, the method comprising: receiving a radio link control (RLC)packet data unit (PDU); transferring an RLC service data unit (SDU)acquired from the RLC PDU from an RLC layer to a packet data convergenceprotocol (PDCP) layer regardless of a number of the RLC PDU; anddeciphering the RLC SDU.
 2. The method of claim 1, wherein the RLC PDUis transferred to the PDCP layer even if the number of the RLC PDU isnot in sequence with a number of a preprocessed RLC PDU.
 3. The methodof claim 1, wherein transferring the RLC SDU comprises: removing an RLCheader of the RLC PDU and storing the RLC SDU in a buffer; andtransferring the RLC SDU stored in the buffer to the PDCP layer even ifa number of the RLC SDU stored in the buffer is not in sequence with anumber of a preprocessed RLC PDU.
 4. The method of claim 1, wherein ifthe RLC SDU is transferred, the PDCP PDU is deciphered regardless of anumber of a PDCP PDU acquired from the RLC SDU.
 5. The method of claim1, further comprising determining whether the RLC SDU is a complete RLCSDU or a segment of the complete RLC SDU, wherein if the RLC SDU is notthe complete RLC SDU, the RLC SDU is not transferred to the PDCP layer.6. The method of claim 5, further comprising determining whether asecond RLC SDU related to the RLC SDU is stored in a buffer if the RLCSDU is the segment of the complete RLC SDU.
 7. The method of claim 6,further comprising: combining the RLC SDU and the second RLC SDU andtransferring the combined RLC SDUs to the PDCP layer if the second RLCSDU is stored; and storing the RLC SDU and then waiting for reception ofthe second RLC SDU if the second RLC SDU is not stored.
 8. The method ofclaim 1, wherein if an RLC SDU that is in sequence with the RLC SDU isstored in a buffer, the RLC SDU and an RLC SDU that is in sequence withthe RLC SDU are simultaneously transferred to the PDCP layer.
 9. Themethod of claim 1, wherein the RLC layer and the PDCP layer use a sharedbuffer.
 10. A reception device, comprising: a transceiver configured totransmit and receive signals; and a controller configured to: receive aradio link control (RLC) packet data unit (PDU), transfer an RLC servicedata unit (SDU) acquired from the RLC PDU from an RLC layer to a packetdata convergence protocol (PDCP) layer regardless of a number of the RLCPDU, and decipher the RLC SDU.
 11. The reception device of claim 10,wherein the controller is further configured to transfer the RLC PDU tothe PDCP layer even if the number of the RLC PDU is not in sequence witha number of a preprocessed RLC PDU.
 12. The reception device of claim10, wherein the controller is further configured to: remove an RLCheader of the RLC PDU, to store the RLC SDU in a buffer, and transferthe RLC SDU stored in the buffer to the PDCP layer even if a number ofthe RLC SDU stored in the buffer is not in sequence with a number of apreprocessed RLC PDU.
 13. The reception device of claim 10, wherein thecontroller is further configured to decipher a PDCP PDU regardless of anumber of a PDCP PDU acquired from the RLC SDU if the RLC SDU istransferred.
 14. The reception device of claim 10, wherein thecontroller is further configured to: determine whether the RLC SDU is acomplete RLC SDU or a segment of the complete RLC SDU, and not transferthe RLC SDU to the PDCP layer if the RLC SDU is not the complete RLCSDU.
 15. The reception device of claim 14, wherein the controller isfurther configured to determine whether a second RLC SDU related to theRLC SDU is stored in a buffer if the RLC SDU is the segment of thecomplete RLC SDU.
 16. The reception device of claim 15, wherein thecontroller is further configured to: combine the RLC SDU and the secondRLC SDU and transfer the combined RLC SDUs to the PDCP layer if thesecond RLC SDU is stored, and wait for reception of the second RLC SDUafter storing the RLC SDU if the second RLC SDU is not stored.
 17. Thereception device of claim 10, wherein the controller is furtherconfigured to simultaneously transfer the RLC SDU and an RLC SDU that isin sequence with the RLC SDU to the PDCP layer if the RLC SDU that is insequence with the RLC SDU is stored in a buffer.
 18. The receptiondevice of claim 10, wherein the RLC layer and the PDCP layer use ashared buffer.